Year	Percent
1991	48.349
1992	48.522
1993	48.478
1994	48.572
1995	48.493
1996	46.483
1997	46.437
1998	46.355
1999	46.268
2000	46.193
2001	46.151
2002	46.115
2003	46.103
2004	46.137
2005	46.215
2006	46.361
2007	46.544
2008	46.757
2009	47.007
2010	47.3
2011	47.638
2012	48.023
2013	48.418
2014	48.757
2015	48.993
2016	49.477
2017	49.744
2018	49.893
2019	49.883
2020	49.732
2021	49.45
2022	49.033